1. Field
The present invention relates to a display device using a light source board.
2. Description of the Related Art
A display device, a display device using liquid crystal for example, is disclosed in FIG. 13 of JP-A-2004-349020. The display device includes: a liquid crystal panel that has a display surface; a light guide plate arranged on a surface opposite to the display surface of the liquid crystal panel to guide light to the liquid crystal panel; and a light source such as a light emitting diode (LED) arranged on a side surface of the light guide plate. By propagating light from a light source in a light guide plate and diffusing the light in a diffusion pattern provided in the light guide plate, the light is extracted onto the display surface.
The display device further includes a middle frame for supporting a light guide plate arranged therein, an optical sheet, and a reflective sheet. The light guide plate has a first surface to face the liquid crystal panel, and a second surface opposite to the first surface. The optical sheet is arranged on the first surface of the light guide plate. The reflective sheet is arranged on the second surface of the light guide plate so as to effectively guide light from the light sources. A light source is arranged on the side surface of the light guide plate. A light source board is formed in the shape of T or L and feeds power from a power supply unit.
In the display device, a middle frame is provided with concave portions that are fitted to protruding portions for position regulation formed on the optical sheet and the light guide plate, thus resulting in a larger frame area of the display device. However, if smaller protruding portions for position regulation are provided on the optical sheet and the light guide plate include so as not to influence the frame area of the display device, this results in dislocation of the optical sheet and the light guide plate due to impact.
When protruding portions for position regulation formed on a light guide plate are arranged on the side surface on the light source side in order to narrow the frame of the display device, it is necessary to provide a T-shaped or L-shaped light source board so as to avoid contact between the protruding portions and the light source board. This involves reduced number of light source boards segmented thus adding to the manufacturing costs.
When a light source board is formed in a linear shape to suppress the increase in the manufacturing costs of a light source board, the light source board is loaded on a light guide plate in close proximity to the power feeding portion, thus increasing the thickness of the entire display device. Further, the optical sheet is deformed by the light source board, which degrades the display quality.